Circulatory System in Mammals Flashcards

1
Q

Describe the pathway of blood through the heart

A

Vena cava, right atrium, right ventricle, pulmonary artery, lungs,
pulmonary vein, left atrium, left ventricle, aorta, body

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2
Q

Name the valves in the heart and describe their location

A

Atrioventricular valves (between atrium and ventricle on
both side). Semi-lunar valves (in the arteries as they leave
the heart)

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3
Q

Compare single and double circulation

A

Single - blood passes through heart once on each circuit of the body.
Double - blood passes through heart twice on each circuit of the body

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4
Q

What does diastole mean?

A

relaxing

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5
Q

What does systole mean?

A

contracting

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6
Q

What is cardiac diastole?

A
  • atria and ventricles relax
  • elastic recoil of the heart lowers the pressure inside the heart chambers and blood returns to the heart and fills the atria.
  • Pressure increases in the atria until the atrioventricular valves open and blood flows into the ventricles.
    -The relaxed atria and ventricles means that the semi-lunar valves are closed.
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7
Q

What is atrial systole?

A

The atria then contract forcing any remaining blood into the ventricles

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8
Q

What is ventricular systole?

A
  • contraction of the ventricles causes the atrioventricular valves to close
  • semi-lunar valves open
  • blood leaves the heart
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9
Q

Explain the volume and pressure changes which take place in the heart during the cardiac cycle

A
  • Atrial systole, the pressure in the heart increases
  • this remains high in ventricular systole
  • As blood leaves the heart and cardiac diastole occurs, the pressure in the heart is lowered
  • As the heart fills with blood this pressure increases.
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10
Q

How are the atria adapted for their function?

A

thin walls and elastic so they can stretch when filled with blood

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11
Q

How are ventricles adapted for their function?

A

thick and muscular walls pump blood under high pressure. Left ventricle is thicker- has to pump blood all around the body

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12
Q

What are the layers that make up blood vessels?

A
  • lumen
  • endothelium
  • elastic layer
  • muscle layer
  • tough fibrous outer layer
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13
Q

How are arteries adapted for their function?

A
  • have a thicker elastic layer and thinner (compared to arterioles) muscle layer, as they have to withstand blood flowing at high pressures . Walls are thicker- to prevent tearing
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14
Q

How are arterioles adapted for their function?

A

Have thinner elastic layer and thicker muscle layer (when compared to arteries) so they can control blood flow.

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15
Q

How are veins adapted for their function?

A
  • have thinner walls as blood is moving at a lower pressure
  • have valves to prevent backflow
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16
Q

Why is a double circulatory system needed in mammals?

A

To maintain blood pressure throughout the body. Otherwise, pressure would drop too low (after being in the lungs) and blood would be unable to flow to all areas of the body

17
Q

How are capillaries adapted for their function?

A
  • walls only one cell thick- short diffusion distance
  • very narrow- RBC pushed flat against walls, increasing SA and time for diffusion
  • numerous and highly branched- large SA
18
Q

What is tissue fluid?

A

a watery liquid containing glucose, amino acids, oxygen and other molecules. It provides these to the cells whilst also removing waste materials

19
Q

How is tissue fluid formed?

A
  • blood flows through a capillary, there is high hydrostatic pressure at the arterial end
  • This forces water and small molecules (oxygen, amino acids, glucose etc.) out of the capillary, leaving behind cells and proteins (ultra-filtration)
20
Q

Explain how water from tissue fluid is returned to the circulatory system

A
  • proteins remain (in blood plasma)
  • (Creates) water potential gradient (lower in the blood)
  • Water moves (to blood) by osmosis
  • Returns (to blood) by lymphatic system
21
Q

Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin

A
  • causes O2 to disassociate more easily
  • by changing/ lowering pH and therefore changing the shape of the haemoglobin
22
Q

Explain how the atrioventricular valve maintains a unidirectional flow of blood

A
  • Pressure in atrium is higher than in ventricle causing valve to open
  • Pressure in ventricle is higher than in atrium causing valve to close
23
Q

Explain why the binding of one molecule of oxygen to haemoglobin makes it easier for a second oxygen molecule to bind

A
  • Binding of first oxygen changes tertiary / quaternary (structure) of haemoglobin
  • This uncovers a second binding site
24
Q

Explain the role of the heart in the formation of tissue fluid

A
  • Contraction of ventricle(s) produces high
    blood/hydrostatic pressure;
  • (This) forces water (and some dissolved
    substances) out (of blood capillaries)
25
Q

What are 4 features of a mammalian circulatory system?

A
  • A suitable medium
  • Means of moving the mediumand maintaining pressure
  • Mechanism to control flow around the body
  • Closed system of vessels
26
Q

What 2 factors impact whether an organism will have a transport system/pump?

A
  • SA to volume ratio
  • how active the organism is
27
Q

How could more red blood cells lead to a heart attack?

A
  • blood thickening
  • can block arteries/clot/slows blood flow
28
Q

Why would high BP lead to accumulation of tissue fluid?

A
  • higher HP
  • increases outward pressure from arterial end of capillary
  • MORE tissue fluid formed